In less than five weeks, Britons will vote on the UK’s membership of the EU. Opinions polls have almost consistently shown the Yes camp to be ahead, thankfully, but the gap bet­ween the two sides is not wide, which means that the vote could go either way. Still, I am cautiously optimistic that the Yes vote will win.

A vote to leave the EU would, of course, be very bad news for the UK, for the EU as a whole, for Britain’s close friends in Europe such as Malta and Ireland, and for the US. A Brexit would also be bad for the global economy, it would send shock waves throughout the international community and it would be a destabilising factor in an already very fragile world order.

A victory for the No side would delight Russia, which would welcome a weakened Europe, as well as the jihadist terrorists, who hate our European values and who feel most threatened when Europe speaks with one voice in condemning and combating their poisoned ideology.

The Yes campaign has so far focused a lot on the economic and diplomatic benefits of Britain remaining in the EU. The No side has focused almost exclusively on migration, and while there are a lot of misconceptions emerging from this camp on the subject, migration will be an very important issue in the referendum and a determining factor for people who vote No.

The economic argument for staying in the EU is clear. The Bank of England, the Treasury, OECD, IMF, Confederation of British Industry and all UK trade unions have warn­ed of severe economic consequen­ces should the UK vote to leave the EU. Such an outcome, they all warn, would lead to less foreign direct investment into Britain, job losses, price rises, a recession, uncertainty, a stock market tumble, economic uncertainty, a weakening of sterling, and a great leap into the dark.

Britain’s economic performance, investor confidence and markets have already slowed simply because a referendum on EU membership is being held, creating a lot of uncertainty. Imagine what would happen if the Leave vote had to win? The No campaign has failed to counter the economic arguments of those pushing for the UK to remain in the EU. They are unable to say what type of economic and trading relationship Britain will have with the EU in a Brexit scenario and have failed to say what price the UK would have to pay for access to the Single Market.

Furthermore, it is important to keep in mind that negotiations for such access would probably take up to 10 years – creating a great deal of un­­certainty – and even if a deal was reached, Britain would have to pay dearly for this privilege and would still have to obey the rules – without having any influence whatsoever in making them. The No side has also failed miserably when it comes to stating how Britain would be able to renegotiate the EU’s 53 trade deals, which the UK would no longer be a part of in the event of a Brexit.

A Brexit would mean the de­par­ture of the EU’s second-largest eco­nomy, which would seriously damage the whole bloc. Europe does not need another economic crisis. How can this be in Britain’s interest?

After the economic argument, the Yes side’s strongest case is without doubt the foreign and security aspect of the debate. Britain today plays a very important global role within the EU and on the international stage – precisely because of its EU membership. Its special relationship with the US would come to nothing if it had to leave the bloc, and this has been made clear by US President Barack Obama.

Furthermore, in the event of a No vote it is very likely that Scotland would secede from the UK, followed perhaps by Wales. The UK as we know it would be no more, and its international standing and clout would be greatly diminished. It is also worth remembering just how important EU membership has been in creating the close relationship between the UK and Ireland after so many years of animosity. A Brexit would put this at risk, and would almost certainly lead to a resumption of sectarian strife in Northern Ireland.

It is certainly not true that Britain’s EU membership curtails its foreign policy, as claimed by the Leave campaigners. The UK can still have a special relationship with the US (which would disappear in the event of a Brexit), it can still ally itself with the US on issues where it is at odds with its EU partners – such as the misguided invasion of Iraq, and it can still have close relations with Commonwealth countries, such as Australia, New Zealand, India and Canada, all of whom want the UK to remain in the bloc.

An EU without the UK would reduce Britain’s foreign policy clout and weaken the bloc as a whole

There are those on the No side who argue that Britain can achieve its foreign policy goals through its Nato membership. This is a complete fallacy – the EU can use its economic and soft power to meet foreign policy goals, which Nato simply cannot do. Can anyone doubt the important role played by the EU’s energy and financial sanctions in convincing Iran to curb its nuclear programme? And surely the EU’s sanctions against Russia for its behaviour in Ukraine have had some effect on Moscow.

An EU without the UK would reduce Britain’s foreign policy clout and weaken the bloc as a whole. Who would benefit from such a situation? The EU needs to be strong and united as its addresses the challenges faced by the turmoil in the Middle East, climate change, a resurgent Russia, nuclear proliferation, jihadist terrorism and the growth of China.

The No campaign’s main argument – and the one that will be a determining factor when people vote to leave the EU – is migration. The right of EU nationals to live and work in the UK is a controversial and emotional issue and many Britons believe these people are taking their jobs, and putting pressure on public services and the welfare system.

Some of the fears expressed by voters about migration are understandable, even if many of the claims are exaggerated. Tony Blair miscalculated badly when, unlike the majority of his EU counterparts, he refused to impose restrictions on the free movement of workers from Eastern Europe for a seven-year transitional period after the 2004 EU enlargement. Sweden and Ireland did the same, but unlike the UK they did not witness large numbers of EU nationals moving to their countries.

It is true that in some areas of the UK a flow of EU migrants has exerted pressure on hospitals, schools and council housing, and this is what people are most concerned about. However, this is due partly to poor management and a shortage of social housing (irrespective of the surge in migrants) which can be rectified. Furthermore, Prime Minister David Cameron’s EU deal which incudes an ‘emergency brake’ on migrants’ in-work benefits for four years and a reduction in benefits for children of EU migrants living overseas, should help curb the number of EU nationals moving to the UK.

The claim, however, that migration is a drain on the welfare state is false. EU migrants for the most part move to Britain to work, and a study by the London School of Economics has shown that they are net contribu­tors to the economy as a result of the taxes they pay.

Also, it is not true that EU migrants are taking the jobs of Britons: the UK today has the lowest unemployment rate since it joined the EEC in 1973.

Equally false is the claim that a Brexit would put an end to the free movement of people into the UK: access access to the Single Market would have to include this principle, something both Norway and Swit­zerland have had to accept.

So the Yes campaign does have some powerful counter-arguments when it comes to migration; it should make them forcefully, while admitting that mistakes were made in the past.

The outcome of the referendum will depend to a great extent on the voter turnout. If the turnout is high, and the younger generation turns out in droves to vote (something they usually do not do), then a Yes vote is almost guaranteed. If the turnout is low – having the referendum on a Thursday does not help and favours elderly retired voters who tend to be anti-EU membership – then the result will be touch and go.

It is also important that civil society and NGOs – representing a cross section of British society, not just businesses and trade unions – speak out loudly in favour of EU membership. Last week, for example, more than 250 celebrities from the arts world signed a letter in The Guardian newspaper urging Britons to vote to remain in the EU. Some of Britain’s best-known artists, musicians and writers warned of the country becoming “an outsider shouting from the wings” if voters opt to leave the EU.

“Britain is not just stronger in Europe, it is more imaginative and more creative. Our global creative success would be severely weakened by walking away,” they warned.

Similarly, a few months ago a cam­paign backed by more than 6,000 British scientists to stay in the EU was launched. Mike Galsworthy, programme director of the Scientists for the EU group, said: “Our scientists have a vision of Britain as an innovative team-player serving our citizenry by proactively tackling challenges of health, energy and environment collaboratively with the rest of Europe.”

The more people with influence speak out, the better the chances of Britain staying in the EU, where it belongs, and avoiding an unnecessary crisis in Europe at this most delicate of times.